Generally it is not ideal to use a traditional CCTV solution on this case, firstly the power supply is a problem, and also if you'd like to receive the videos through your computer at home, 3G surveillance solution is often not very stable and not widely used.
Have you considered of using a car dash camera? Maybe this will be more applicable in this situation. There cameras can record in VGA or HD720P or HD1080P format, and many of them built-in with rechargeable battery which can work for about 3-4 hours. For your situation, maybe you need one with "auto park" function, that means when your car is in parking mode, if someone touch your car, the motion detective feature will trigger the camera to start record, and usually such cameras are very mini in size. Y
